Solution for chiller/hp units, energy efficiency and reliability

The new CAREL standard application solution for chillers/heat pumps with scroll and BLDC compressors has been developed around the new c.pCO family range of programmable controllers.

This application can manage both air/water and water/water units. The maximum configuration involves three compressors in each circuit, with up to two circuits.

The distinctive feature of this solution is high efficiency. The CAREL software application offers the best high efficiency solution for all chiller configurations, using BLDC technology for rotary or scroll compressors and the EXV electronic expansion valve.

Flexible use and savings with DC technology and the power+ inverter

The use of DC compressors guarantees higher energy efficiency than any other technology available on the market, with a very wide range of cooling capacity modulation.

The main features of DC technology are low noise, an excellent compressor size-power ratio, less maintenance and longer appliance life, due to the reduced number of ON-OFF cycles. This application covers more than 50 models of BLDC compressors made by different manufacturers, tested and certified in its labs. This guarantees complete control of the compressor envelope at different frequencies, with the objective of ensuring operation in the most ideal conditions for the compressor and thus ensuring maximum reliability.

Unit efficiency and stable control

Efficiency and stable operation guaranteed by two distinct types of temperature control:

PID control at start-up;

PID control in steady operation.

Control at start-up needs to prevent excess capacity being called. Indeed, as when starting the exact status of the units (the load) is not known, capacity needs to be delivered gradually, awaiting the reaction from the system. Control in steady operation, on the other hand, needs to be reactive, so as to respond quickly to any variations in load and keep the water outlet temperature as close as possible to the set point.

The built-in serial ports on the c.pCO family controllers moreover allow information to be exchanged with the unit actuators (electronic valves, fan controllers, compressor inverter etc.), thus optimising unit control and efficiency according to system requirements.

Unit protection

When developing this software, special attention was also focused on protecting the devices on the chiller/heat pump units.

Complete management of the compressor envelope allows the device to in safe conditions at all times, thus guaranteeing the highest performance. Indeed, whenever the compressor working work approaches one of the operating limits defined by the envelope, specific prevention actions are adopted, involving varying compressor capacity (for BLDC compressors), condenser fan speed of condensation (on air/water units) and the opening of the electronic valve. The protection function is available for both BLDC compressors and ON/OFF scroll compressors.

New frost protection management based on the evaporator probe and not the water outlet probe, so as to ensure more accurate reading of evaporator operating conditions. If current conditions indicate the presence of ice on the evaporator, the frost protection function is activated after a delay time, which varies based on the difference between the evaporation temperature and the frost protection threshold, following a hyperbolic relationship that imitates the real behaviour of ice formation on the heat exchanger. The delay is also calculated according to the type of heat exchanger used (tube bundle or plates).